The present invention relates to the installation of sealant materials in conduits to repair leaks, and is particularly related to a packer and its use in installing grout for repairing leaks in underground pipes.
It has been well known for years that underground pipes can be repaired in place by installation of thin flexible liners impregnated with materials that cure to harden the liners and cause them to adhere to the interior surfaces of a pipe needing repair. While these systems work well in pipes that are straight and have good access via manholes the uniqueness of smaller interconnecting pipes with limited access increases the costs and diminishes the economic value.
For repair of localized defects in pipes, such as a defect along a particular part of the length of a pipe, it is known to install various types of grouting materials into the surrounding strata to seal and support by blocking the interior of the conduit or pipe at locations near opposite ends of a defective portion of the pipe, and then forcing grout material under pressure to the exterior of the pipe.
Various known packers isolate a short length of a conduit such as a sewer pipe and fill the majority of the interior space within the section of the pipe to be repaired, leaving a thin annular space between the packer and the interior surface of the defective portion of the pipe, so that a sealant such as grout can be installed in the annular space and can then be supported in place while the sealant cures to a desired degree before the packer is removed. While some such packers have proved to be effective in large pipes, where the interior of the pipe is easily accessible through manholes or other access ports, practical packers that can negotiate tight bends for use in smaller conduits have not been available, and repair of smaller underground conduits by sealing defects without excavation has been more difficult to accomplish.
Particularly in smaller sewers, to which access is available substantially only through cleanout pipes whose interior diameter is less than the interior diameter of the sewer pipes themselves, installation of grout has been difficult to accomplish, and effective repair has required excavation in more cases than is desired.
Additionally, in repair of smaller-diameter conduits, the risks involved in attempting to repair such pipes by using a relatively inexpensive fast-setting more dense cementitious grout, rather than a softer compressible chemical grouting material, as currently used in the market has been avoided, since hardening of a cementitious grout within a packer at a significant distance from the point of access to the pipe being repaired could require very expensive excavation in order to remove the packer. Packers on the market deliver the grout through tubing inside of the packer. If the tubing were to leak cementitious grout inside the packer, the potential exists to lock the device in place at a location with only very limited and expensive access.
On the other hand, use of chemical grout materials to fill voids in the soil surrounding leaking underground conduits is also undesirably costly and has an arguable performance.
What is desired, then, is a packer that can be inserted into underground and other conduits that are accessible only with difficulty, so that repairs of such conduits can be effected in situ by installation of sealant materials such as various types of grouting material, including cementitious grouting material, without undue risk of sealant material solidifying inside the packer device and becoming captured inside the conduit and requiring excavation or otherwise difficult and expensive operations to retrieve the packer and effect repair of the conduit.